Can crusher

ABSTRACT

A can crusher having a reciprocating plunger which slides in a semicylindrical chamber to crush cans, and the like. The cans are fed into the chamber by one or more pivoting fingers arranged between adjacent, spaced rods forming a can supporting surface. A return movement of the plunger following a can crushing stroke actuates a linkage that pivots a can into the chamber, which has been left vacant by the previously crushed can passing through a slot at the end of the chamber. A pair of pins affixed to a finger supporting shaft are engaged by a pivoted lever to achieve the can feeding motion.

United States Patent 1191 Bischoff June 18, 1974 1 CAN CRUSHER [76] Inventor: Jack W. Bischoff, PO. Box 174,

Lovell, Wyo. 82431 [22] Filed:

Oct. 27, 1972 [2]] Appl. No.: 301,584

52 use! ..100/100, lO0/DIG.2, 100/216, .100/218, l0O/283, 221/268 51 lnt.Cl B301 15/30 [58] Field of Search 100/100, DIG. 2, 215, 218, 100/282, 216, 283; 221/251, 254, 286

[56] References Cited UNITED STATES PATENTS 969,720 9/1910 Pickett..; IOU/DIG. 2 1,850,134 3/1932 Myer...'... 100/283 X 2.748.693 6/1956 Drain et a1... 100/215 X 2,960.928 11/1960 Anderson i IOO/DIG. 2 3,048,096 8/1962 Guedel IOO/DIG. 2 3.062.130 11/1962 Huber et a1 lOO/DIG. 2

3,659.520 5/1972 Garrett et a1. 100/216 Primary Examiner-Billy J. Wilhite Attorney, Agent, or Firm-Clarence A. OBrien; Harvey B. Jacobson 5 7 ABSTRACT A can crusher having a reciprocating plunger which slides in a semicylindrical chamber to crush cans, and the like. The cans are fed into the chamber by one or more pivoting fingers arranged between adjacent, spaced rods forming a can supporting surface. A re turn movement of the plunger following a can crushing stroke actuates a linkage that pivots a can into the chamber, which has been left vacant by the previously crushed can passing through a slot at the end of the chamber. A pair of pins affixed to a finger supporting shaft are engaged by a pivoted lever to achieve the can feeding motion.

14 Claims, 7 Drawing Figures CAN CRUSHER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to article crushing apparatus, and in particular to apparatus for crushing beverage cans, and the like.

2. Description of the Prior Art Among the advantages of using aluminum beverage containers is that economic factors make it possible to recycle the cans, and the like, and reclaim the aluminum, thus solving a refuse problem. This recycling is particular advantageous for commercial beverage establishments, and the like, who may accumulate large quantities of containers in a given period of time. Further, scrap dealers may gather together large quantities of reclaimable containers from various sources. However, the problem arises as to storage of these containers before shipment. Even when a container is constructed from a metal, other than aluminum, for which the economics are not favorable for reclamation, stor age of empty containers is a problem.

Apparatus has been proposed for crushing cans, and the like, examples of which may be found in US. Pat. Nos. 1,434,417 2,619,150, 3,412,675, and 3,659,520.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for crushing or smashing beverage cans and the like which will operate smoothly and quietly, and is simple of construction.

It is another object of the present invention to provide a can crusher which will operate with a minimum of supervision.

It is yet another object of the present invention to provide a can crusher which will crush all standard types of metallic containers.

These and other objects are achieved according to the present invention by providing a can crusher which has an arrangement for positively feeding articles, such as cans, into a crushing, or compressing arrangement.

A preferred embodiment of a crushing arrangement, according to the present invention, has an article holding member having a semicylindrical wall defining a semicylindrical chamber and an opening communicat ing with the chamber. This opening is arranged to re ceive an article. An anvil plate is mounted on and spaced from a one end of the semicylindrical wall for forming a slot adjacent thereto for removing crushed articles from the chamber. A cylindrical plunger is slidably arranged in the chamber, and passes through an open end of the holding member arranged opposite the one end. This plunger is connected to a rotatable crank to form a slide crank mechanism therewith.

A preferred embodiment of a feeding arrangement, according to the present invention, has at least one pivotally mounted finger arranged for engaging an article during a pivoting movement thereof and moving the article through the opening and into the chamber. An article storage section advantageously forms a portion of the feeding arrangement. This storage section may have a sloping article supporting surface formed by a plurality of spaced, parallel, longitudinal elements,

2 such as rods, and at least one finger is arranged between adjacent ones of these elements.

The finger is pivoted by an arrangement having a support member affixed on the storage section. A lever is pivotally connected to this support member, and a guide is mounted on, for example, the holding member.

A longitudinal slide is arranged in this guide for longitudinal sliding movement with respect thereto, and a link pivotally connects the slide to the lever. A shaft on which the finger is mounted for movement therewith is pivotally mounted on, for example, the storage section. A pair of guide pins are affixed to this shaft and arranged extending therefrom in different angular directions for cooperating with the lever. The lever is arranged between these guide pins for engaging same and pivoting the shaft. A projection is affixed to the slide and arranged for abutting the end of the plunger outside the holding member. A spring is connected to and arranged between this projection and the semicylindrical wall for biasing the slide toward the semicylindrical wall. The guide pins are arranged such that an article will be fed into the chamber by a pivotal movement of the feeding finger when the plunger is being withdrawn from the chamber.

According to an advantageous feature of the present invention, a pivotally mounted retainer member is provided on the storage section. A linkage between the fin ger shaftand this retainer member, which is preferably in the form of a bar, causes it to pivot with and oppositely to the finger and retain an article adjacent the article being fed and prevent same from interferring with the feeding process.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like: parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view showing a can crusher according to the present invention.

FIG. 2 is an end elevational view showing the can crusher of FIG. 1.

FIG. 3 is a top plan view, partly cut away, showing the can crusher of FIGS. 1 and 2.

FIG. 4 is a fragmentary, side elevational, sectional view, showing a feeding arrangement for a can crusher, according to the present invention.

FIG. 5 is a fragmentary, bottom plan view, showing the arrangement of FIG. 4.

FIG. 6 is a fragmentary, side elevational, sectional view, similar to FIG. 4, but showing various elements in a different position.

FIG. 7 is a fragmentary, bottom plan view, similar to FIG. 5, but showing various elements in their FIG. 6 position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 of the drawings show a can crusher 10 according to the present invention having an article crushing arrangement 12 and a positive article feeding arrangement 14.

Crushing arrangement 12 preferably includes an article holding member 16 having a semicylindrical wall 18 defining a semicylindrical chamber 20 and an opening 22 communicating with chamber 20. This opening 22 is arranged to receive an article 24, which may be a beverage container and the like. An anvil plate 26 is mounted on and spaced from a one end of holding member 16 so as to form a slot 28 adjacent plate 26 for removing crushed articles from chamber 20. Anvil plate 26 may be mounted on wall 18 of holding member 16 in a suitable, known manner, as by rods 30 and 32.

Arrangement 12 further includes a cylindrical plunger 34 slidably arranged in holding member 16 and passing through an open end 36 thereof opposite the one end adjacent anvil plate 26. This plunger 34 is connected to a rotatable crank in the form of a, for example, disk 38 as by a connecting rod 40 to form a slide crank mechanism therewith.

An arrangement 42 is advantageously provided for rotating disk 38. This arrangement 42 includes a, for example, conventional electric motor 44, a belt 46 arranged around spaced, parallel pulleys 48 and 50 for transmitting power to a suitable, known gear box 52. This gear box 52 has an output shaft 53 upon which disk 38 is mounted for rotation thereby. All of the structure of can crusher 10, according to the present invention, that is, arrangements 12, 14, and 42 are conveniently mounted in a known manner on a, for example, cart 52 for ease in transporting crusher from one place to another.

Arrangement 14 preferably includes a plurality of pivotally mounted fingers 56 arranged for engaging an article 24 during a pivoting movement and moving the article 24 through opening 22 and into chamber 20. Arrangement 14 also includes an article storage section 58 having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements such as, for example, rods 60. Fingers 56 are arranged between adjacent ones of these rods 60. Storage section 58 also has a pair of spaced, parallel side guide walls 62, and transverse bracing members such as member 64 for forming a rigid framework.

Fingers 56 may be pivoted by a mechanism which includes a support member 66 affixed on storage section 58. A lever 68 is pivotally connected to support member 66 in a known manner, and a cylindrical guide 70 is mounted on holding member 16. A longitudinal slide 72 is arranged in guide 70 for longitudinal sliding movement with respect thereto, and a link 74 (FIGS. 5 and 7) pivotally connects slide 72 to an end of lever 68 opposite the end pinned to support member 66. Fingers 56 are mounted on a shaft 76 for movement therewith, and shaft 76 is pivotally mounted to, for example, guide walls 62. A pair of guide pins 78 and 80 are affixed to shaft 76 and extend therefrom in different angular directions, as can best be seen from FIGS. 5 and 7 of the drawings. Lever 68 is arranged between the guide pins 78 and 80 for engaging same and pivoting shaft 76.

The pivoting mechanism further includes a projection 82 affixed to slide 72 and arranged for abutting the end of plunger 34 which is outside of holding member 16. A spring 84, which may be a conventional helical coil, tension spring, is connected to and arranged between the projection 82 and holding member 16 for biasing slide 72 toward anvil plate 26. Guide pins 78 and 80 are arranged for performance of an article feeding, pivotal movement of fingers 56 when plunger 34 is being withdrawn from chamber 20.

Arrangement 14 further includes a retainer bar 86 pivotally mounted in a known manner as on side guide walls 62 and provided with a crank arm 88. This crank arm 88 pivots with bars 86. A crank arm 90 is affixed to shaft 76, and a link 92 is pivotally connected to the crank arms. Crank arms 88 and 90, and link 92 are arranged for pivoting retainer bar 86 with and oppositely t0 fingers 56 for retaining article 24 adjacent the article 24 being fed and preventing the adjacent article 24 from interferring with the feeding process. A guide bar 94 may also be mounted on guide wall 62 for preventing the adjacent article 24 from moving perpendicularly to the article supporting surface and out of the storage section 58.

The sequence of operation for arrangements 12 and 14 of a can crusher 10, according to the present invention, will now be explained in conjunction with FIGS. 4 to 7 of the drawings. Once the device is assembled, one or more articles 24 are placed in storage section 58. Advantageously, storage section 58 has at least two trays 96 and 98 (FIG. 2) connected together in series. If article 24 is a standard 12 ounce beverage can, each tray 96, 98 may hold, for example, seven cans. Desirably, article 24 is a hollow cylinder having a pair of spaced ends, and is crushed perpendicular to the plane of these ends. Upon actuation of motor 44, disk 38 will be rotated for reciprocating plunger 34. As plunger 34 is withdrawn from chamber 20 of holding member 16, lever 68 will be moved from the position shown in FIGS. 4 and 5 of the drawings to the position shown in FIGS. 6 and 7 of the drawings, whereby fingers 56 will be pivoted from a position beneath the article 24 adjacent the holding members 16, as shown in FIGS. 4 and 5, to a position such as shown in FIGS. 6 an 7. This pivotal movement will cause fingers 56 to engage the adjacent article 24 and lift same over rod 30, through opening 22, and into chamber 20. When the article 24 has been deposited in chamber 20, plunger 34 will be in the position shown in FIG. 7. Now, the direction of travel of plunger 34 will reverse and the plunger 34 will move toward the position shown in FIG. 5. The article 24 will be crushed, and will then fall through slot 28 into a, for example, suitable container placed below the apparatus. The above cycle then repeats. While fingers 56 were pivoting the article 24 into chamber 20, bar 86 was being lowered into the position shown in FIG. 6 so as to block the movement of the next article 24 on tray 96 from moving into the position previously occupied by the article 24 being fed. When fingers 56 are pivoted back to their FIG. 4 position, bar 86 will be raised to its FIG. 4 position, thus permitting the previously retained article 24 to move into the position vacated by the previously fed article 24.

A can crusher 10, according to the present invention, operates in a smooth and quiet manner which makes it suitable for use even in the home. By proper dimensioning of chamber 20, all kinds and sizes of cans may be crushed, cutting down on storage space for even those waste cans which are not recyclable. The flat top 100 on cart 54 provides a surface for placing articles 24 to be crushed before these articles are arranged in storage section 58. So simple is a can crusher 10, according to the present invention, that it may be controlled by one conventional on-off switch (not shown). This switch would be connected to motor 44 for starting and stopping same.

The provision of retainer bar 86 and the positive feed of an article 24 into chamber by fingers 56 prevents the articles 24 waiting in storage section 58 to be crushed from being displaced by the action of plunger 34 against an article 24 arranged in chamber 20. A smooth, trouble fee operation results.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A can crusher, comprising, in combination:

a. means for crushing an article, the crushing means including an article holding member having a semicylindrical wall defining a semicylindrical chamber and an opening communicating with the chamber, the opening being arranged to receive an article, an anvil plate connected to and spaced from a one end of the holding member for forming a slot adjacent the anvil plate for removing crushed articles from the chamber, the crushing means further including a cylindrical plunger slidably arranged in the holding member and passing through an open end opposite the one end, and connected to a rotatable crank to form a slide crank mechanism therewith, further including means for rotating the crank of the slide crank, and a cart, and wherein the rotating, crushing and feeding means are mounted on the cart; and

b. means for positively feeding an articles to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article through the opening and into the chamber, and means for pivoting the finger, the feeding means further including an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements, the pivoting means including a support member affixed on the storage section, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins afiixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.

2. A structure as defined in claim 1, wherein the feeding means further includes a projection affixed to the slide and arranged for abutting the end of the plunger outside the holding member, and a spring connected to and arranged between the projection and the holding member for biasing the slide toward the anvil plate, the guide pins being arranged for an article feeding, pivotal movement of the finger when the plunger is being withdrawn from the chamber.

3. A structure as defined in claim 1, wherein the feeding means further includes a pivotally mounted retainer means, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms andd link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.

4. A structure as defined in claim 1, wherein the article is a hollow cylinder having a pair of spaced ends, and is crushed perpendicular to these ends.

5. A can crusher, comprising, in combination:

a. means for crushing an article;

b. means for positively feeding an article to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article to the crushing means, the feeding means further including an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements; and

. means for pivoting the finger, said means ncluding a support member affixed on the storage section, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins affixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.

6. A structure as defined in claim 5, wherein the crushing means includes an article holding member having a semicylindrical wall defining a semicylindrical chamber and an opening communicating with the chamber, the opening being arranged to receive an article, an anvil plate connected to and spaced from a one end of the holding member for forming a slot adjacent the anvil plate for removing crushed articles from the chamber.

7. A structure as defined in claim 6, wherein the crushing means further includes a. cylindrical plunger slidably arranged in the holding member and passing through an open end opposite the one end, and connected to a rotatable crank to form a slide crank mechanism therewith.

8. A structure as defined in claim 7, further including means for rotating the crank of the slide crank, and a cart, and wherein the rotating, crushing and feeding means are mounted on the cart.

9. A structure as defined in claim 5, wherein the feeding means further includes a projection affixed to the slide and arranged for abbuting the end of the plunger outside the holding member, and a spring connected to and arranged between the projection and the holding member for biasing the slide toward the anvil plate, the guide pins being arranged for an article feeding, pivotal movement of the finger when the plunger is being withdrawn from the chamber.

10. A structure as defined in claim 9, wherein the feeding means further includes a pivotally mounted retainer member, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms and link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.

11. A structure as defined in claim 5, wherein the feeding means further includes a pivotally mounted retainer member, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms and link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.

12. A structure as defined in claim 5, wherein the article is a hollow cylinder having a pair of spaced ends, and is crushed perpendicular to these ends.

13, A can crusher, comprising, in combination:

a. means for crushing an article;

b. means for positively feeding an article to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article to the crushing means; and

c. means for pivoting the finger, the pivoting mens forming part of the feeding means and including a stationary support member, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a pivotably mounted shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins affixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.

14. A structure as defined in claim 13, wherein the feeding means further includes an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements. 

1. A can crusher, comprising, in combination: a. means for crushing an article, the crushing means including an article holding member having a semicylindrical wall defining a semicylindrical chamber and an opening communicating with the chamber, the opening being arranged to receive an article, an anvil plate connected to and spaced from a one end of the holding member for forming a slot adjacent the anvil plate for removing crushed articles from the chamber, the crushing means further including a cylindrical plunger slidably arranged in the holding member and passing through an open end opposite the one end, and connected to a rotatable crank to form a slide crank mechanism therewith, further including means for rotating the crank of the slide crank, and a cart, and wherein the rotating, crushing and feeding means are mounted on the cart; and b. means for positively feeding an articles to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article through the opening and into the chamber, and means for pivoting the finger, the feeding means further including an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements, the pivoting means including a support member affixed on the storage section, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins affixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.
 2. A structure as defined in claim 1, wherein the feeding means further includes a projection affixed to the slide and arranged for abutting the end of the plunger outside the holding member, and a spring connected to and arranged between the projection and the holding member for biasing the slide toward the anvil plate, the guide pins being arranged for an article feeding, pivotal movement of the finger when the plunger is being withdrawn from the chamber.
 3. A structure as defined in claim 1, wherein the feeding means further includes a pivotally mounted retainer means, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms andd link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.
 4. A structure as defined in claim 1, wherein the article is a hollow cylinder having a pair of spaced ends, and is crushed perpendicular to these ends.
 5. A can crusher, comprising, in combination: a. means for crushing an article; b. means for positively feeding an article to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article to the crushing means, the feeding means further including an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements; and c. means for pivoting the finger, said means ncluding a support member affixed on the storage section, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins affixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.
 6. A structure as defined in claim 5, wherein the crushing means includes an article holding member having a semicylindrical wall defining a semicylindrical chamber and an opening communicating with the chamber, the opening being arranged to receive an article, an anvil plate connected to and spaced from a one end of the holding member for forming a slot adjacent the anvil plate for removing crushed articles from the chamber.
 7. A structure as defined in claim 6, wherein the crushing means further includes a cylindrical plunger slidably arranged in the holding member and passing through an open end opposite the one end, and connected to a rotatable crank to form a slide crank mechanism therewith.
 8. A structure as defined in claim 7, further including means for roTating the crank of the slide crank, and a cart, and wherein the rotating, crushing and feeding means are mounted on the cart.
 9. A structure as defined in claim 5, wherein the feeding means further includes a projection affixed to the slide and arranged for abbuting the end of the plunger outside the holding member, and a spring connected to and arranged between the projection and the holding member for biasing the slide toward the anvil plate, the guide pins being arranged for an article feeding, pivotal movement of the finger when the plunger is being withdrawn from the chamber.
 10. A structure as defined in claim 9, wherein the feeding means further includes a pivotally mounted retainer member, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms and link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.
 11. A structure as defined in claim 5, wherein the feeding means further includes a pivotally mounted retainer member, and a first crank arm connected to the retaining member for pivotal movement therewith, a second crank arm affixed to the shaft, and a further link pivotally connected to the crank arms, the crank arms and link arranged for pivoting the retainer member with and oppositely to the finger and retaining an article adjacent the article being fed.
 12. A structure as defined in claim 5, wherein the article is a hollow cylinder having a pair of spaced ends, and is crushed perpendicular to these ends.
 13. A can crusher, comprising, in combination: a. means for crushing an article; b. means for positively feeding an article to the crushing means, the feeding means including at least one pivotally mounted finger arranged for engaging an article during a pivoting movement and moving the article to the crushing means; and c. means for pivoting the finger, the pivoting mens forming part of the feeding means and including a stationary support member, a lever pivotally connected to the support member, a guide, a longitudinal slide arranged in the guide for longitudinal sliding movement, a link pivotally connected to the slide and lever, a pivotably mounted shaft, the finger mounted on the shaft for movement therewith, a pair of guide pins affixed to the shaft and extending therefrom in different angular directions, the lever arranged between the guide pins for engaging same and pivoting the shaft.
 14. A structure as defined in claim 13, wherein the feeding means further includes an article storage section having a sloping, article supporting surface formed by a plurality of spaced, parallel, longitudinal elements, and the finger is arranged between adjacent ones of these elements. 